Re: [Cpptool-develop] Back on CPP-Refactoring ...

[Baptiste L. <gai...@fr...>]

Welcome back Andre. I been fairly drained by work for the last month too.
Though, I did divert a bit of time working on CppUnit V2.

I ported the 'mini parser' core to python last week-end, so it would be
easier to prototype a robust parser implementation. Current results are v=
ery
positive. You can find it in src/pyrfta/test/rfta/parser.py and
parsertest.py. To run it, just install python 2.2 (you can get it from
python.org), and run src/pyrfta/test/alltests.py. Notes that the parser u=
se
a tokenizer.

Personnally, I would be enclined to move the full parser to python (it ta=
kes
a lot of less time to produce code in python), and only move it back to C=
++
when it's the only way remaining to improve performance. Python is a very
simple language to grasp (about 2 hours to go through the tutorial), and =
its
dynamic nature make it very malleable.

For instance, "::NameSpace::MyClass::myVar" is parsed using the following
parser instantiation (it's actual python code):
nested_id_p =3D (maybe_p( "::" ) >> list_p( id_p,
symbol_p('::') ))[inline_child_at_a(1)]['nested_id']

=3D> it parse for an optinal '::' at the beginning, the a list of id sepa=
rated
by '::'. The trailing code in square brackets are action used to manipula=
te
the produced tree and name the resulting node.

Parsing '::NameSpace::MyClass::myVar'
    Node(nested_id : 6 children)
    |-Token(symbol,'::')
    |-Token(id,'NameSpace')
    |-Token(symbol,'::')
    |-Token(id,'MyClass')
    |-Token(symbol,'::')
    |-Token(id,'myVar')

I still need to add an action to filter out the '::' that occurs in the
list, but that's it.

A dummy 'class' declaration parser I wrote (just to experiment), look lik=
e
this:

class_inheritance_p =3D maybe_p( (symbol_p( ":" )  >>  anyuntil_p(
"{" ))['inheritance'] )
null_statement_p =3D eos_p['null_statement']
class_body_statements_p =3D null_statement_p
class_inheritance_and_body_decl_p =3D class_inheritance_p >> "{" >>
maybe_p(class_body_statements_p)  >> "}"

class_decl_p =3D (symbol_p("class") | "struct") >> nested_id_p  \
               >> maybe_p( class_inheritance_and_body_decl_p ) >> eos_p

Which produce the following tree when parsing:
Parsing 'class MyClass : public MyParent<MyClass,simple_traits> { };'
    Node(? : 5 children)
    |-Token(symbol,'class')
    |-Node(nested_id : 2 children)
    |-|-NONE
    | |-Token(id,'MyClass')
    |-NONE
    |-Node(? : 4 children)
    | |-Node(inheritance : 2 children)
    | | |-Token(symbol,':')
    | | |-Node(? : 7 children)
    | | | |-Token(symbol,'public')
    | | | |-Token(id,'MyParent')
    | | | |-Token(symbol,'<')
    | | | |-Token(id,'MyClass')
    | | | |-Token(symbol,',')
    | | | |-Token(id,'simple_traits')
    | | | |-Token(symbol,'>')
    | |-Token(symbol,'{')
    |-|-NONE
    | |-Token(symbol,'}')
    |-Token(symbol,';')

The inheritance is not parsed here, because I'd like to implement a mecan=
ism
to make a local parsing. We know were the inheritance declaration starts =
and
ends, this should help parsing potential templated inheritance more
robustly, doing a 'sub parsing' on the specific token range.

The interesting part is that you can still write 'hand written' parser to
handle real weird case if needed. There is still much to work out, but it=
's
really promising.

Baptiste.

----- Original Message -----=20
From: "Andre Baresel" <and...@gm...>
To: "CppTool Mailing List" <Cpp...@li...>
Sent: Monday, July 28, 2003 5:30 PM
Subject: [Cpptool-develop] Back on CPP-Refactoring ...


> Hello together,
>
> I'm back from workaholic days and 2 weeks holiday -
>
> I had some stressful and horrible days at work, after this two nice wee=
k
> holiday
> in austria and one week at a conference in chicago...
>
> Now I'm a little bit more relaxed and there's time for some coding.
> I plan to play arround with some refactoring at code level,
> just to use the new features of the parser and show what's
> possible with our implementation ...
>
> until later,
> andr=E9